Mounting B4 zooms on the BMPCC MFT mount

Blackmagic Pocket Cinema Camera

We have a Blackmagic Pocket Cinema Camera
on demo, and are experimenting with various (older) lenses, including building a rig to
use 2/3" B4 zoom lenses with the BMPCC. The tables below show frame-grabs
from our tests to assess vignetting and focus at different focal lengths and apertures
(F4, F2.8 and wide open), with and without using a doubler (where the lens
has one).

This video (above) contains a few shots of Salford taken on my way home, using a Canon J11x4.5 B4 lens on a BMPCC. It's intended just to show the range of shot sizes that can be obtained
from a single lens, from very wide to telephoto, so there was no planning and
not much finesse to it, no power to the zoom servo (ie jerky zooms), etc.

Fujinon A7x7 (used) - £80.00

This is a used Fujinon A7x7 SD 2/3"
broadcast B4 wide-angle servo-zoom lens, pictured and tested below. The lens has a focal length of
7-50mm and a minimum focusing distance of .3M (1ft). Lens hood and
front cap included.

Fujinon A7x7 BRM-28

This SD B4 wide-angle lens has a focal length of
7-50mm
and a maximum aperture of F1.7. It neither includes a x2 doubler, nor does not
feature internal focusing, and is probably from the 1990s(?). However, it
does seem to produce an above-average circle of light so scores well in
terms of not vignetting.

Focal length

Doubler used?

at F4

at F2.8

at F1.7

10 mm

N/A

20 mm

N/A

50 mm

N/A

F4

F2.8

F1.7

OK for:-

Use at F4+ and from ~10mm upwards

Use at all focal lengths when cropping in post. Allows a clean
1280x720 to be extracted from the native 1920x1080 on the BMPCC.

Not so good for:-

Use as a telephoto, as max focal length is 50mm

Fujinon A10x4.8 BERM-28

This broadcast SD B4 wide-angle lens has a focal length of
4.8-48mm
and a maximum aperture of F1.8. It includes a x2 doubler, and
features internal focusing. This lens also has a macro mode.

Focal length

Doubler used?

at F4

at F2.8

at F1.8

4.8 mm

No

9 mm

No

15 mm

No

24 mm

No

48 mm

No

96 mm

Yes (x2)

50 mm

Yes (x2)

20 mm

Yes (x2)

9.6 mm

Yes (x2)

F4

F2.8

F1.8

OK for:-

Use without the doubler at F4+ and above ~24mm

Use at all focal lengths when cropping in post. Allows a clean
1280x720 to be extracted from the native 1920x1080 on the BMPCC.

Cropped super-wide-angle shots

Not so good for:-

Use in low light (when using the doubler)

Extreme telephoto, but goes to 96mm with doubler

Fujinon A14x9 BERM-28 Pegasus

This SD B4 standard lens has a focal length of
9-126mm and a maximum aperture of F1.7. It includes a x2 doubler, but does
not feature internal focusing, which gives some indication of its age
(1990s). This lens also has a macro mode.

Focal length

Doubler used?

at F4

at F2.8

at F1.7

9 mm

No

20 mm

No

40 mm

No

80 mm

No

126 mm

No

160 mm

Yes (x2)

80 mm

Yes (x2)

40 mm

Yes (x2)

18 mm

Yes (x2)

F4

F2.8

F1.7

OK for:-

Use without the doubler at F4+ and above ~60mm

Use at all focal lengths when cropping in post. Allows a clean
1280x720 to be extracted from the native 1920x1080 on the BMPCC.

Not so good for:-

Use in low light (when using the doubler)

Getting wider angles that don't vignette

Canon J14x8 B4 IRS

This SD B4 standard lens has a focal length of 8-112mm
and a maximum aperture of F1.7. It includes a x2 doubler, but does not
feature internal focusing, which gives some indication of its age
(1980s/90s). This lens also has a macro mode.

Focal length

Doubler used?

at F4

at F2.8

at F1.7

8 mm

No

20 mm

No

40 mm

No

80 mm

No

112 mm

No

80 mm

Yes (x2)

40 mm

Yes (x2)

20 mm

Yes (x2)

16 mm

Yes (x2)

F4

F2.8

F1.7

OK for:-

Use without the doubler at F4+ and above ~60mm

Use at all focal lengths when cropping in post. Allows a clean
1280x720 to be extracted from the native 1920x1080 on the BMPCC.

Not so good for:-

Use in low light (when using the doubler)

Getting wider angles that don't vignette

Getting a totally vignette-free image without the doubler -
even at longer focal lengths slight edge shading still persists.

Canon J15x9.5B4 KRS

This SD B4 standard lens has a focal length
of 9.5-143mm and a maximum aperture of F1.8. It neither includes a x2
doubler, nor does not feature internal focusing, and is probably from the
1990s(?). Some versions of this lens also have a macro mode, although this
particular lens doesn't.

Focal length

Doubler used?

at F4

at F2.8

at F1.8

9.5 mm

N/A

20 mm

N/A

40 mm

N/A

60 mm

N/A

80 mm

N/A

143 mm

N/A

F4

F2.8

F1.8

OK for:-

Use at F4+ and from ~60mm upwards

Use at all focal lengths when cropping in post. Allows a clean
1280x720 to be extracted from the native 1920x1080 on the BMPCC.

Not so good for:-

Use in non-cropped mode, as it vignettes at most focal lengths in
the bottom half of its range

Lighting in modern office buildings

Inspired by the techniques shown at the
IOV Videoskills Roadshows,
in this short video Martin talks about, and
demonstrates, the benefits of using lighting when filming in modern office
buildings. With modern cameras able to get a well exposed picture in fairly low
light, it's easy to forget what a difference lighting can make.

What we're about . . .
ZEN is not a traditional Audio-Visual dealer who started selling computers,
nor is it a computer shop that also sells video products. You won't
get any salesmen giving you the "hard-sell" when you call, just
straightforward advice and information - which for some callers is the
knowledge that they don't need to buy whatever it is they thought they
needed! Above all you'll be dealing with someone with a wide range of
experience and knowledge of both PCs and video production. We're not the
biggest, nor necessarily the cheapest, but we are one of the longest
established computer/video specialists in the UK.

Company history . . .
ZEN was started in the 1980s by Martin Kay, then working for ITV at
Granada's Manchester studios, who built his first 6502-based computer in
1979 from an Ohio Scientific kit, bought in the USA whilst working as a
Sound Recordist on a
film shoot for World In Action. With the advent of the Amiga, which could be gen-locked
to a video source, Martin started writing a variety of video-related software. This
included subtitling & tele-prompting, ident clocks, scoring software for
sports & gameshows, and specialist software to mimic other computer
displays for
use in TV film dramas like Cracker, Prime Suspect and A Touch of Frost.
Martin left Granada in 1993 to concentrate on his computer-video activities
with ZEN, following a natural path into non-linear editing systems,
for many years the main business activity, although he still maintains an active
interest in video production.